Valorization of Juglans regia. L Bark Residues as a Natural Colorant Based on Response Surface Methodology: A Challenging Approach to a Sustainable Dyeing Process for Acrylic Fabrics

Development and Optimization of a Sustainable Process Assisted by Microwave Energy to Dye Cellulosic Fabrics by Juglans regia Barks Residues Extract

Juglans regia barks contain a diversity of phenolic compounds. Two of the most important groups of phenolic compounds are tannins, and flavonoids. These latter, possess different antioxidant, anti-inflammatory, and antibacterial properties. This paper explores the usefulness of dyeing cellulosic fabrics, namely cotton, with Juglans regia barks residues extract. The dyeing process proposed was assisted by microwave energy. The impact of the main dyeing conditions (percentage of cationizing agent, pH, dyeing duration, and microwave power) on the color strength (K/S) and the L*, a*, b*, C*, and h* coordinates were studied. Optimization experiments were carried out using a definitive screening type plan (MINITAB 19). It was found that the best conditions to achieve the dyeing of cellulosic fabrics were: a pH of 6.23; a percentage of cationizing agent of 6.5%; a microwave power of 690 W, and a dyeing duration of 4.5 min.